The Monastery is where pious monks create illustrated manuscripts of religious text. These are then delivered to your keep for your library and earn you honour. You can also create 2 military units in your monastery, Fighting Monks and Warrior Monks.
Stone Required - 100
Gold required - 1000
Workers Required - 6
The treasury is where your gold is stored and where you can set the tax rates. The Baliff works here and if you have extra estates he will occasionally ride over to them to collect the taxes there too.
Stone Required - 10
Workers Required - 1
*) denotes a former staff member.